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Merge bounds handling into _DimensionalMetadata class. (#7)
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* Merge bounds handling into _DimensionalMetadata class.

* Fix cube arithmetic bug.

* Code style fix.
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@pp-mo @lbdreyer
pp-mo authored and lbdreyer committed Oct 23, 2019
1 parent 77e4b3f commit d3f39b8
Showing 1 changed file with 82 additions and 71 deletions.
153 changes: 82 additions & 71 deletions lib/iris/coords.py
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,13 @@ def __init__(self, values, standard_name=None, long_name=None,
A dictionary containing other cf and user-defined attributes.
"""
# Note: this class includes bounds handling code for convenience, but
# this can only run within instances which are also Coords, because
# only they may actually have bounds. This parent class has no
# bounds-related getter/setter properties, and no bounds keywords in
# its __init__ or __copy__ methods. The only bounds-related behaviour
# it provides is a 'has_bounds()' method, which always returns False.

#: CF standard name of the quantity that the metadata represents.
self.standard_name = standard_name

Expand All @@ -111,6 +118,7 @@ def __init__(self, values, standard_name=None, long_name=None,
# Set up DataManager attributes and values.
self._values_dm = None
self._values = values
self._bounds_dm = None # Only ever set on Coord-derived instances.

def __getitem__(self, keys):
"""
Expand All @@ -124,6 +132,9 @@ def __getitem__(self, keys):
indexing.
"""
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.

# Fetch the values.
values = self._values_dm.core_data()

Expand All @@ -137,20 +148,15 @@ def __getitem__(self, keys):

# If the metadata is a coordinate and it has bounds, repeat the above
# with the bounds.
if isinstance(self, Coord):
if self.has_bounds():
bounds = self._bounds_dm.core_data()
_, bounds = iris.util._slice_data_with_keys(bounds, keys)
bounds = bounds.copy()
else:
bounds = None

copy_args = dict(points=values, bounds=bounds)
else:
copy_args = dict(values=values)
copy_args = {}
if self.has_bounds():
bounds = self._bounds_dm.core_data()
_, bounds = iris.util._slice_data_with_keys(bounds, keys)
# Pass into the copy method : for Coords, it has a 'bounds' key.
copy_args['bounds'] = bounds.copy()

# The new metadata is a copy of the old one with replaced content.
new_metadata = self.copy(**copy_args)
new_metadata = self.copy(values, **copy_args)

return new_metadata

Expand All @@ -166,6 +172,8 @@ def copy(self, values=None):
copied.
"""
# Note: this is overridden in Coord subclasses, to add bounds handling
# and a 'bounds' keyword.
new_metadata = copy.deepcopy(self)
if values is not None:
new_metadata._values_dm = None
Expand Down Expand Up @@ -262,6 +270,8 @@ def _str_dates(self, dates_as_numbers):
**kwargs)

def __str__(self):
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.
if self.units.is_time_reference():
fmt = '{cls}({values}{bounds}' \
', standard_name={self.standard_name!r}' \
Expand Down Expand Up @@ -289,6 +299,8 @@ def __str__(self):
return result

def __repr__(self):
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.
fmt = '{cls}({self._values!r}{bounds}' \
', standard_name={self.standard_name!r}, units={self.units!r}' \
'{other_metadata})'
Expand All @@ -302,6 +314,9 @@ def __repr__(self):
return result

def __eq__(self, other):
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.

eq = NotImplemented
# If the other object has a means of getting its definition, then do
# the comparison, otherwise return a NotImplemented to let Python try
Expand All @@ -310,9 +325,19 @@ def __eq__(self, other):
# metadata comparison
eq = self._as_defn() == other._as_defn()
# data values comparison
if eq:
if eq and eq is not NotImplemented:
eq = iris.util.array_equal(self._values, other._values,
withnans=True)

# Also consider bounds, if we have them.
# (N.B. though only Coords can ever actually *have* bounds).
if eq and eq is not NotImplemented:
if self.has_bounds() and other.has_bounds():
eq = iris.util.array_equal(self.bounds, other.bounds,
withnans=True)
else:
eq = not self.has_bounds() and not other.has_bounds()

return eq

def __ne__(self, other):
Expand Down Expand Up @@ -352,23 +377,47 @@ def __binary_operator__(self, other, mode_constant):
object would represent "10 kilometers".
"""
result = NotImplemented
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.

if (isinstance(other, _DimensionalMetadata) or
not isinstance(other, (int, float, np.number))):

def typename(obj):
if isinstance(obj, Coord):
result = 'Coord'
else:
# We don't really expect this, but do something anyway.
result = self.__class__.__name__
return result

emsg = '{selftype} {operator} {othertype}'.format(
selftype=typename(self),
operator=self._MODE_SYMBOL[mode_constant],
othertype=typename(other))
raise iris.exceptions.NotYetImplementedError(emsg)

if isinstance(other, (int, float, np.number)):
values = self._values_dm.core_data()
else:
# 'Other' is an array type : adjust points, and bounds if any.
result = NotImplemented

if mode_constant == self._MODE_ADD:
new_values = values + other
elif mode_constant == self._MODE_SUB:
new_values = values - other
elif mode_constant == self._MODE_MUL:
new_values = values * other
elif mode_constant == self._MODE_DIV:
new_values = values / other
elif mode_constant == self._MODE_RDIV:
new_values = other / values
def op(values):
if mode_constant == self._MODE_ADD:
new_values = values + other
elif mode_constant == self._MODE_SUB:
new_values = values - other
elif mode_constant == self._MODE_MUL:
new_values = values * other
elif mode_constant == self._MODE_DIV:
new_values = values / other
elif mode_constant == self._MODE_RDIV:
new_values = other / values
return new_values

new_values = op(self._values_dm.core_data())
result = self.copy(new_values)
if self.has_bounds():
result.bounds = op(self._bounds_dm.core_data())

return result

Expand Down Expand Up @@ -403,12 +452,18 @@ def __rmul__(self, other):
return self * other

def __neg__(self):
return self.copy(-self._core_values())
values = -self._core_values()
copy_args = {}
if self.has_bounds():
copy_args['bounds'] = -self.core_bounds()
return self.copy(values, **copy_args)

def convert_units(self, unit):
"""Change the units, converting the values of the metadata."""
# If the coord has units convert the values in points (and bounds if
# present).
# Note: this method includes bounds handling code, but it only runs
# within Coord type instances, as only these allow bounds to be set.
if self.units.is_unknown():
raise iris.exceptions.UnitConversionError(
'Cannot convert from unknown units. '
Expand Down Expand Up @@ -1396,17 +1451,6 @@ def _repr_other_metadata(self):
result += ', climatological={}'.format(self.climatological)
return result

def __eq__(self, other):
eq = super(Coord, self).__eq__(other=other)

if eq and eq is not NotImplemented:
if self.has_bounds() and other.has_bounds():
eq = iris.util.array_equal(self.bounds, other.bounds,
withnans=True)
else:
eq = self.bounds is None and other.bounds is None
return eq

def _as_defn(self):
defn = CoordDefn(self.standard_name, self.long_name, self.var_name,
self.units, self.attributes, self.coord_system,
Expand All @@ -1422,39 +1466,6 @@ def _as_defn(self):
def __hash__(self):
return hash(id(self))

def __binary_operator__(self, other, mode_constant):
if isinstance(other, Coord):
emsg = 'coord {} coord'.format(
self._MODE_SYMBOL[mode_constant])
raise iris.exceptions.NotYetImplementedError(emsg)

new_coord = super(Coord, self).__binary_operator__(
other=other, mode_constant=mode_constant)

if new_coord is not NotImplemented:
if self.has_bounds():
bounds = self._bounds_dm.core_data()

if mode_constant == self._MODE_ADD:
new_bounds = bounds + other
elif mode_constant == self._MODE_SUB:
new_bounds = bounds - other
elif mode_constant == self._MODE_MUL:
new_bounds = bounds * other
elif mode_constant == self._MODE_DIV:
new_bounds = bounds / other
elif mode_constant == self._MODE_RDIV:
new_bounds = other / bounds

else:
new_bounds = None
new_coord.bounds = new_bounds
return new_coord

def __neg__(self):
return self.copy(-self.core_points(),
-self.core_bounds() if self.has_bounds() else None)

def convert_units(self, unit):
"""
Change the coordinate's units, converting the values in its points
Expand Down

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